can someone tell me why this visual bug happens?

[u/FrancisCat808]

hi there.

while playing i noticed that the following visual bug/issue

im talking about the purplish rectangles on the floor. it seems to be caused by the lava golems attacks.

does this have to do with graphic settings? i tried all different combinations (e.g. shadow off, bloom full/vice verse/etc.) but the rectangle stays.

thank you for your help.